Dragon crossing the river is also known as Hu, centipede (southern Yunnan materia medica), ground brush (central China plant), Lycopodium, Platycladus orientalis (Guizhou folk prescription collection), Lycopodium, Lycopodium, Leymus chinensis, Pinus massoniana (Hunan medical record), Monkey grass, Monkey tail, Shujincao and so on. Lycopodium floor brush, perennial herb. Stolon creeping; The erect stem is 30-40 cm high and yellow-green; The vegetative branches are flat and fan-shaped. Leaves slightly crossed and opposite, 4 rows; The lateral two rows of leaves are scaly rhomboid, extending downward and healing, with sharp apex and bending towards the ventral surface. The back leaves are linear-lanceolate, and the apex is short and sharp, sandwiched between the two leaves; The ventral leaves are small, scaly, subulate, 1/3- 1/2 times as large as the dorsal leaves, and the spines are short. Spore branches are much higher than lateral vegetative branches, and the top branches diverge twice; The top of the last branch has 1 sporangium spike; Spore leaves are broadly ovoid, with sharp apex, irregular fine teeth at the edge and stipe at the base. Sporangium is round and kidney-shaped. Spores are tetrahedral and spherical, with reticulation and small protrusions.